Background： Identification of the proper femoral intramedullary （IM） access point is an important determinant of final implant position in IM-guided total knee arthroplasty （TKA）. The aim of this study was to ide...Background： Identification of the proper femoral intramedullary （IM） access point is an important determinant of final implant position in IM-guided total knee arthroplasty （TKA）. The aim of this study was to identify the optimal entry point in Chinese participants using a new three-dimensional method. Methods： A series of computed tomography scans of 44 femurs in Chinese participants from October 2014 to October 2015 were imported into Mimics 17.0 software to identify the optimal entry point. The apex of the intercondylar notch （AIN） was used as the reference bony anatomical landmark to identify the proper entry point to insert the IM rod. The statistical significance was calculated on the basis of a 5% level （P 〈 0.05） using the Student＇s t-test. Results： For the males, the average ideal entry point was 1.49 mm medial and 13.39 mm anterior to the AIN. The values were 1.77 mm medial and 15.29 mm anterior to the AIN in females. A significant difference was present between males and females （13.39 ±2.46 mm vs. 15.29 ± 3.44 mm, t = 2.124, P = 0.040）. When using the recommended location as the entry point for the IM rod, the mean potential error differed significantly from the femoral trochlear groove （the potential error of IM in males in coronal plane： 0.93~ ±0.24~ vs. 1.27~ ± 0.32~, t = -4.166, P 〈 0.001; the potential error of 1M in males in sagittal plane： 1.40° ± 0.42° vs. 2.79° ± 0.70°, t = -7.155, P 〈 0.001; the potential error oflM in females in coronal plane： 0.73° ± 0.28° vs. 1.15° ± 0.35°, t = -3.940, P 〈 0.001 ： and the potential error of 1M in females in sagittal plane： 1.48° ±0.47° vs. 2.76° ± 0.83°, t = -5.574, P 〈 0.001 ）. A significant difference was present between the recommended point and the point 10 mm anterior to the origin of the posterior cruciate ligament （the potential error of IM in males in coronal plane： 0.93° ± 0.24° vs. 1.53° ±0.43°, t = -5.948, P 〈 0.001 ; the potential error of IM in males in sagi展开更多
The Karakoram Highway(KKH),a part of the China–Pakistan Economic Corridor(CPEC),is a major highway connecting northern Pakistan to China.The inventorying and analysis of landslides along KKH are challenging because o...The Karakoram Highway(KKH),a part of the China–Pakistan Economic Corridor(CPEC),is a major highway connecting northern Pakistan to China.The inventorying and analysis of landslides along KKH are challenging because of poor accessibility,vast study area,limited availability of ground-based datasets,and the complexity of landslide processes in the region.In order to preserve life,property,and infrastructure,and to enable the uninterrupted and efficient operation of the KKH,it is essential to strengthen measures for the prevention and control of geological disasters.In the present study,SBASInSAR(Small Baseline Subsets-Interferometric Synthetic Aperture Radar)was used to process 150 scenes of Sentinel 1-A images in the year 2017 along the Karakoram Highway.A total of 762 landslides,including 57 complex landslides,126 rock falls,167 debris slides,and 412 unstable slopes,ranging in size between 0.0017 and 10.63 km2 were identified.Moreover,this study also gains an inventory of 40 active glacier movements in this region.Landslide categorization,displacements characteristics,spatial distribution,and their relationship with various contributing factors have been successfully investigated along the entire KKH using image interpretation and frequency-area statistics.The criteria adopted for landslides categorization is presented in the study.The results showed that the 2-D ground deformation derived in Hunza valley echoes well with the general regional landslides characteristics.The spatial distribution analysis revealed that there are clumped distributions of landslides in the Gaizi,Tashkurgan,and Khunjerab in China,as well as in Hunza valley,and north of Chilas city in Pakistan.Statistical results indicated that these landslides mainly occur on south-facing slopes with a slope angle of 20°–45°and elevation relief of 550–2,100 m.Landslide development is also related to low vegetation cover and weathering effects in mountain gullies.Overall,our study provides scientific data support and theoretical references for p展开更多
文摘Background： Identification of the proper femoral intramedullary （IM） access point is an important determinant of final implant position in IM-guided total knee arthroplasty （TKA）. The aim of this study was to identify the optimal entry point in Chinese participants using a new three-dimensional method. Methods： A series of computed tomography scans of 44 femurs in Chinese participants from October 2014 to October 2015 were imported into Mimics 17.0 software to identify the optimal entry point. The apex of the intercondylar notch （AIN） was used as the reference bony anatomical landmark to identify the proper entry point to insert the IM rod. The statistical significance was calculated on the basis of a 5% level （P 〈 0.05） using the Student＇s t-test. Results： For the males, the average ideal entry point was 1.49 mm medial and 13.39 mm anterior to the AIN. The values were 1.77 mm medial and 15.29 mm anterior to the AIN in females. A significant difference was present between males and females （13.39 ±2.46 mm vs. 15.29 ± 3.44 mm, t = 2.124, P = 0.040）. When using the recommended location as the entry point for the IM rod, the mean potential error differed significantly from the femoral trochlear groove （the potential error of IM in males in coronal plane： 0.93~ ±0.24~ vs. 1.27~ ± 0.32~, t = -4.166, P 〈 0.001; the potential error of 1M in males in sagittal plane： 1.40° ± 0.42° vs. 2.79° ± 0.70°, t = -7.155, P 〈 0.001; the potential error oflM in females in coronal plane： 0.73° ± 0.28° vs. 1.15° ± 0.35°, t = -3.940, P 〈 0.001 ： and the potential error of 1M in females in sagittal plane： 1.48° ±0.47° vs. 2.76° ± 0.83°, t = -5.574, P 〈 0.001 ）. A significant difference was present between the recommended point and the point 10 mm anterior to the origin of the posterior cruciate ligament （the potential error of IM in males in coronal plane： 0.93° ± 0.24° vs. 1.53° ±0.43°, t = -5.948, P 〈 0.001 ; the potential error of IM in males in sagi
基金supported by National Key Research and Development Program of China(Grant No.2017YFC1501005)National Natural Science Foundation of China(Grant Nos.41661144046,42007232)+3 种基金the Science and Technology Major Project of Gansu Province(Grant No.19ZD2FA002)the Science and Technology Planning Project of Gansu Province(Grant No.18YF1WA114)the Fundamental Research Funds for the Central Universities(Grant Nos.lzujbky-2021-ey05)Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0902)。
文摘The Karakoram Highway(KKH),a part of the China–Pakistan Economic Corridor(CPEC),is a major highway connecting northern Pakistan to China.The inventorying and analysis of landslides along KKH are challenging because of poor accessibility,vast study area,limited availability of ground-based datasets,and the complexity of landslide processes in the region.In order to preserve life,property,and infrastructure,and to enable the uninterrupted and efficient operation of the KKH,it is essential to strengthen measures for the prevention and control of geological disasters.In the present study,SBASInSAR(Small Baseline Subsets-Interferometric Synthetic Aperture Radar)was used to process 150 scenes of Sentinel 1-A images in the year 2017 along the Karakoram Highway.A total of 762 landslides,including 57 complex landslides,126 rock falls,167 debris slides,and 412 unstable slopes,ranging in size between 0.0017 and 10.63 km2 were identified.Moreover,this study also gains an inventory of 40 active glacier movements in this region.Landslide categorization,displacements characteristics,spatial distribution,and their relationship with various contributing factors have been successfully investigated along the entire KKH using image interpretation and frequency-area statistics.The criteria adopted for landslides categorization is presented in the study.The results showed that the 2-D ground deformation derived in Hunza valley echoes well with the general regional landslides characteristics.The spatial distribution analysis revealed that there are clumped distributions of landslides in the Gaizi,Tashkurgan,and Khunjerab in China,as well as in Hunza valley,and north of Chilas city in Pakistan.Statistical results indicated that these landslides mainly occur on south-facing slopes with a slope angle of 20°–45°and elevation relief of 550–2,100 m.Landslide development is also related to low vegetation cover and weathering effects in mountain gullies.Overall,our study provides scientific data support and theoretical references for p
